1 files changed, 455 insertions, 5 deletions

diff --git a/src/libcharon/plugins/kernel_libipsec/kernel_libipsec_ipsec.c b/src/libcharon/plugins/kernel_libipsec/kernel_libipsec_ipsec.c
index c7fc56b71..efa519a83 100644
--- a/src/libcharon/plugins/kernel_libipsec/kernel_libipsec_ipsec.c
+++ b/src/libcharon/plugins/kernel_libipsec/kernel_libipsec_ipsec.c
@@ -18,6 +18,7 @@
 #include <ipsec.h>
 #include <hydra.h>
 #include <networking/tun_device.h>
+#include <threading/mutex.h>
 #include <utils/debug.h>
 
 typedef struct private_kernel_libipsec_ipsec_t private_kernel_libipsec_ipsec_t;
@@ -38,9 +39,174 @@ struct private_kernel_libipsec_ipsec_t {
 	 * TUN device
 	 */
 	tun_device_t *tun;
+
+	/**
+	 * Mutex to lock access to various lists
+	 */
+	mutex_t *mutex;
+
+	/**
+	 * List of installed policies (policy_entry_t)
+	 */
+	linked_list_t *policies;
+
+	/**
+	 * List of exclude routes (exclude_route_t)
+	 */
+	linked_list_t *excludes;
+};
+
+typedef struct exclude_route_t exclude_route_t;
+
+/**
+ * Exclude route definition
+ */
+struct exclude_route_t {
+	/** Destination address to exclude */
+	host_t *dst;
+	/** Source address for route */
+	host_t *src;
+	/** Nexthop exclude has been installed */
+	host_t *gtw;
+	/** References to this route */
+	int refs;
 };
 
 /**
+ * Clean up an exclude route entry
+ */
+static void exclude_route_destroy(exclude_route_t *this)
+{
+	this->dst->destroy(this->dst);
+	this->src->destroy(this->src);
+	this->gtw->destroy(this->gtw);
+	free(this);
+}
+
+/**
+ * Find an exclude route entry by destination address
+ */
+static bool exclude_route_match(exclude_route_t *current,
+								host_t *dst)
+{
+	return dst->ip_equals(dst, current->dst);
+}
+
+typedef struct route_entry_t route_entry_t;
+
+/**
+ * Installed routing entry
+ */
+struct route_entry_t {
+	/** Name of the interface the route is bound to */
+	char *if_name;
+	/** Source ip of the route */
+	host_t *src_ip;
+	/** Destination net */
+	chunk_t dst_net;
+	/** Destination net prefixlen */
+	u_int8_t prefixlen;
+	/** Reference to exclude route, if any */
+	exclude_route_t *exclude;
+};
+
+/**
+ * Destroy a route_entry_t object
+ */
+static void route_entry_destroy(route_entry_t *this)
+{
+	free(this->if_name);
+	DESTROY_IF(this->src_ip);
+	chunk_free(&this->dst_net);
+	free(this);
+}
+
+/**
+ * Compare two route_entry_t objects
+ */
+static bool route_entry_equals(route_entry_t *a, route_entry_t *b)
+{
+	return a->if_name && b->if_name && streq(a->if_name, b->if_name) &&
+		   a->src_ip->ip_equals(a->src_ip, b->src_ip) &&
+		   chunk_equals(a->dst_net, b->dst_net) && a->prefixlen == b->prefixlen;
+}
+
+typedef struct policy_entry_t policy_entry_t;
+
+/**
+ * Installed policy
+ */
+struct policy_entry_t {
+	/** Direction of this policy: in, out, forward */
+	u_int8_t direction;
+	/** Parameters of installed policy */
+	struct {
+		/** Subnet and port */
+		host_t *net;
+		/** Subnet mask */
+		u_int8_t mask;
+		/** Protocol */
+		u_int8_t proto;
+	} src, dst;
+	/** Associated route installed for this policy */
+	route_entry_t *route;
+	/** References to this policy */
+	int refs;
+};
+
+/**
+ * Create a policy_entry_t object
+ */
+static policy_entry_t *create_policy_entry(traffic_selector_t *src_ts,
+										   traffic_selector_t *dst_ts,
+										   policy_dir_t dir)
+{
+	policy_entry_t *this;
+	INIT(this,
+		.direction = dir,
+	);
+
+	src_ts->to_subnet(src_ts, &this->src.net, &this->src.mask);
+	dst_ts->to_subnet(dst_ts, &this->dst.net, &this->dst.mask);
+
+	/* src or dest proto may be "any" (0), use more restrictive one */
+	this->src.proto = max(src_ts->get_protocol(src_ts),
+						  dst_ts->get_protocol(dst_ts));
+	this->src.proto = this->src.proto ? this->src.proto : 0;
+	this->dst.proto = this->src.proto;
+	return this;
+}
+
+/**
+ * Destroy a policy_entry_t object
+ */
+static void policy_entry_destroy(policy_entry_t *this)
+{
+	if (this->route)
+	{
+		route_entry_destroy(this->route);
+	}
+	DESTROY_IF(this->src.net);
+	DESTROY_IF(this->dst.net);
+	free(this);
+}
+
+/**
+ * Compare two policy_entry_t objects
+ */
+static inline bool policy_entry_equals(policy_entry_t *a,
+									   policy_entry_t *b)
+{
+	return a->direction == b->direction &&
+		   a->src.proto == b->src.proto &&
+		   a->dst.proto == b->dst.proto &&
+		   a->src.mask == b->src.mask &&
+		   a->dst.mask == b->dst.mask &&
+		   a->src.net->equals(a->src.net, b->src.net) &&
+		   a->dst.net->equals(a->dst.net, b->dst.net);
+}
+
+/**
  * Expiration callback
  */
 static void expire(u_int32_t reqid, u_int8_t protocol, u_int32_t spi, bool hard)
@@ -106,14 +272,229 @@ METHOD(kernel_ipsec_t, flush_sas, status_t,
 	return ipsec->sas->flush_sas(ipsec->sas);
 }
 
+/**
+ * Add an explicit exclude route to a routing entry
+ */
+static void add_exclude_route(private_kernel_libipsec_ipsec_t *this,
+							  route_entry_t *route, host_t *src, host_t *dst)
+{
+	exclude_route_t *exclude;
+	host_t *gtw;
+
+	if (this->excludes->find_first(this->excludes,
+								  (linked_list_match_t)exclude_route_match,
+								  (void**)&exclude, dst) == SUCCESS)
+	{
+		route->exclude = exclude;
+		exclude->refs++;
+	}
+
+	if (!route->exclude)
+	{
+		DBG2(DBG_KNL, "installing new exclude route for %H src %H", dst, src);
+		gtw = hydra->kernel_interface->get_nexthop(hydra->kernel_interface,
+												   dst, NULL);
+		if (gtw)
+		{
+			char *if_name = NULL;
+
+			if (hydra->kernel_interface->get_interface(
+									hydra->kernel_interface, src, &if_name) &&
+				hydra->kernel_interface->add_route(hydra->kernel_interface,
+									dst->get_address(dst),
+									dst->get_family(dst) == AF_INET ? 32 : 128,
+									gtw, src, if_name) == SUCCESS)
+			{
+				INIT(exclude,
+					.dst = dst->clone(dst),
+					.src = src->clone(src),
+					.gtw = gtw->clone(gtw),
+					.refs = 1,
+				);
+				route->exclude = exclude;
+				this->excludes->insert_last(this->excludes, exclude);
+			}
+			else
+			{
+				DBG1(DBG_KNL, "installing exclude route for %H failed", dst);
+			}
+			gtw->destroy(gtw);
+			free(if_name);
+		}
+		else
+		{
+			DBG1(DBG_KNL, "gateway lookup for %H failed", dst);
+		}
+	}
+}
+
+/**
+ * Remove an exclude route attached to a routing entry
+ */
+static void remove_exclude_route(private_kernel_libipsec_ipsec_t *this,
+								 route_entry_t *route)
+{
+	char *if_name = NULL;
+	host_t *dst;
+
+	if (!route->exclude || --route->exclude->refs > 0)
+	{
+		return;
+	}
+	this->excludes->remove(this->excludes, route->exclude, NULL);
+
+	dst = route->exclude->dst;
+	DBG2(DBG_KNL, "uninstalling exclude route for %H src %H",
+		 dst, route->exclude->src);
+	if (hydra->kernel_interface->get_interface(
+									hydra->kernel_interface,
+									route->exclude->src, &if_name) &&
+		hydra->kernel_interface->del_route(hydra->kernel_interface,
+									dst->get_address(dst),
+									dst->get_family(dst) == AF_INET ? 32 : 128,
+									route->exclude->gtw, route->exclude->src,
+									if_name) != SUCCESS)
+	{
+		DBG1(DBG_KNL, "uninstalling exclude route for %H failed", dst);
+	}
+	exclude_route_destroy(route->exclude);
+	route->exclude = NULL;
+	free(if_name);
+}
+
+/**
+ * Install a route for the given policy
+ *
+ * this->mutex is released by this function
+ */
+static bool install_route(private_kernel_libipsec_ipsec_t *this,
+	host_t *src, host_t *dst, traffic_selector_t *src_ts,
+	traffic_selector_t *dst_ts, policy_entry_t *policy)
+{
+	route_entry_t *route, *old;
+	host_t *src_ip;
+	bool is_virtual;
+
+	if (policy->direction != POLICY_OUT)
+	{
+		this->mutex->unlock(this->mutex);
+		return TRUE;
+	}
+
+	if (hydra->kernel_interface->get_address_by_ts(hydra->kernel_interface,
+									src_ts, &src_ip, &is_virtual) != SUCCESS)
+	{
+		this->mutex->unlock(this->mutex);
+		return FALSE;
+	}
+
+	INIT(route,
+		.if_name = strdup(this->tun->get_name(this->tun)),
+		.src_ip = src_ip,
+		.dst_net = chunk_clone(policy->dst.net->get_address(policy->dst.net)),
+		.prefixlen = policy->dst.mask,
+	);
+
+	if (policy->route)
+	{
+		old = policy->route;
+
+		if (route_entry_equals(old, route))
+		{	/* such a route already exists */
+			route_entry_destroy(route);
+			this->mutex->unlock(this->mutex);
+			return TRUE;
+		}
+		/* uninstall previously installed route */
+		if (hydra->kernel_interface->del_route(hydra->kernel_interface,
+									old->dst_net, old->prefixlen, NULL,
+									old->src_ip, old->if_name) != SUCCESS)
+		{
+			DBG1(DBG_KNL, "error uninstalling route installed with policy "
+				 "%R === %R %N", src_ts, dst_ts, policy_dir_names,
+				 policy->direction);
+		}
+		route_entry_destroy(old);
+		policy->route = NULL;
+	}
+
+	/* if remote traffic selector covers the IKE peer, add an exclude route */
+	if (dst_ts->includes(dst_ts, dst))
+	{
+		/* add exclude route for peer */
+		add_exclude_route(this, route, src, dst);
+	}
+
+	DBG2(DBG_KNL, "installing route: %R src %H dev %s",
+		 dst_ts, route->src_ip, route->if_name);
+
+	switch (hydra->kernel_interface->add_route(hydra->kernel_interface,
+							route->dst_net, route->prefixlen, NULL,
+							route->src_ip, route->if_name))
+	{
+		case ALREADY_DONE:
+			/* route exists, do not uninstall */
+			remove_exclude_route(this, route);
+			route_entry_destroy(route);
+			this->mutex->unlock(this->mutex);
+			return TRUE;
+		case SUCCESS:
+			/* cache the installed route */
+			policy->route = route;
+			this->mutex->unlock(this->mutex);
+			return TRUE;
+		default:
+			DBG1(DBG_KNL, "installing route failed: %R src %H dev %s",
+				 dst_ts, route->src_ip, route->if_name);
+			remove_exclude_route(this, route);
+			route_entry_destroy(route);
+			this->mutex->unlock(this->mutex);
+			return FALSE;
+	}
+}
+
 METHOD(kernel_ipsec_t, add_policy, status_t,
 	private_kernel_libipsec_ipsec_t *this, host_t *src, host_t *dst,
 	traffic_selector_t *src_ts, traffic_selector_t *dst_ts,
 	policy_dir_t direction, policy_type_t type, ipsec_sa_cfg_t *sa, mark_t mark,
 	policy_priority_t priority)
 {
-	return ipsec->policies->add_policy(ipsec->policies, src, dst, src_ts,
-									   dst_ts, direction, type, sa, mark, priority);
+	policy_entry_t *policy, *found = NULL;
+	status_t status;
+
+	if (type != POLICY_IPSEC)
+	{
+		return SUCCESS;
+	}
+
+	status = ipsec->policies->add_policy(ipsec->policies, src, dst, src_ts,
+								dst_ts, direction, type, sa, mark, priority);
+	if (status != SUCCESS)
+	{
+		return status;
+	}
+	/* we track policies in order to install routes */
+	policy = create_policy_entry(src_ts, dst_ts, direction);
+
+	this->mutex->lock(this->mutex);
+	if (this->policies->find_first(this->policies,
+								  (linked_list_match_t)policy_entry_equals,
+								  (void**)&found, policy) == SUCCESS)
+	{
+		policy_entry_destroy(policy);
+		policy = found;
+	}
+	else
+	{	/* use the new one, if we have no such policy */
+		this->policies->insert_last(this->policies, policy);
+	}
+	policy->refs++;
+
+	if (!install_route(this, src, dst, src_ts, dst_ts, policy))
+	{
+		return FAILED;
+	}
+	return SUCCESS;
 }
 
 METHOD(kernel_ipsec_t, query_policy, status_t,
@@ -129,19 +510,82 @@ METHOD(kernel_ipsec_t, del_policy, status_t,
 	traffic_selector_t *dst_ts, policy_dir_t direction, u_int32_t reqid,
 	mark_t mark, policy_priority_t priority)
 {
-	return ipsec->policies->del_policy(ipsec->policies, src_ts, dst_ts,
-									   direction, reqid, mark, priority);
+	policy_entry_t *policy, *found = NULL;
+	status_t status;
+
+	status = ipsec->policies->del_policy(ipsec->policies, src_ts, dst_ts,
+										 direction, reqid, mark, priority);
+
+	policy = create_policy_entry(src_ts, dst_ts, direction);
+
+	this->mutex->lock(this->mutex);
+	if (this->policies->find_first(this->policies,
+								  (linked_list_match_t)policy_entry_equals,
+								  (void**)&found, policy) != SUCCESS)
+	{
+		policy_entry_destroy(policy);
+		this->mutex->unlock(this->mutex);
+		return status;
+	}
+	policy_entry_destroy(policy);
+	policy = found;
+
+	if (--policy->refs > 0)
+	{	/* policy is still in use */
+		this->mutex->unlock(this->mutex);
+		return status;
+	}
+
+	if (policy->route)
+	{
+		route_entry_t *route = policy->route;
+
+		if (hydra->kernel_interface->del_route(hydra->kernel_interface,
+				route->dst_net, route->prefixlen, NULL, route->src_ip,
+				route->if_name) != SUCCESS)
+		{
+			DBG1(DBG_KNL, "error uninstalling route installed with "
+						  "policy %R === %R %N", src_ts, dst_ts,
+						   policy_dir_names, direction);
+		}
+		remove_exclude_route(this, route);
+	}
+	this->policies->remove(this->policies, policy, NULL);
+	policy_entry_destroy(policy);
+	this->mutex->unlock(this->mutex);
+	return status;
 }
 
 METHOD(kernel_ipsec_t, flush_policies, status_t,
 	private_kernel_libipsec_ipsec_t *this)
 {
-	return ipsec->policies->flush_policies(ipsec->policies);
+	policy_entry_t *pol;
+	status_t status;
+
+	status = ipsec->policies->flush_policies(ipsec->policies);
+
+	this->mutex->lock(this->mutex);
+	while (this->policies->remove_first(this->policies, (void*)&pol) == SUCCESS)
+	{
+		if (pol->route)
+		{
+			route_entry_t *route = pol->route;
+
+			hydra->kernel_interface->del_route(hydra->kernel_interface,
+					route->dst_net, route->prefixlen, NULL, route->src_ip,
+					route->if_name);
+			remove_exclude_route(this, route);
+		}
+		policy_entry_destroy(pol);
+	}
+	this->mutex->unlock(this->mutex);
+	return status;
 }
 
 METHOD(kernel_ipsec_t, bypass_socket, bool,
 	private_kernel_libipsec_ipsec_t *this, int fd, int family)
 {
+	/* we use exclude routes for this */
 	return NOT_SUPPORTED;
 }
 
@@ -155,6 +599,9 @@ METHOD(kernel_ipsec_t, destroy, void,
 	private_kernel_libipsec_ipsec_t *this)
 {
 	ipsec->events->unregister_listener(ipsec->events, &this->ipsec_listener);
+	this->policies->destroy_function(this->policies, (void*)policy_entry_destroy);
+	this->excludes->destroy(this->excludes);
+	this->mutex->destroy(this->mutex);
 	free(this);
 }
 
@@ -188,6 +635,9 @@ kernel_libipsec_ipsec_t *kernel_libipsec_ipsec_create()
 			.expire = expire,
 		},
 		.tun = lib->get(lib, "kernel-libipsec-tun"),
+		.mutex = mutex_create(MUTEX_TYPE_DEFAULT),
+		.policies = linked_list_create(),
+		.excludes = linked_list_create(),
 	);
 
 	ipsec->events->register_listener(ipsec->events, &this->ipsec_listener);